The present invention relates to the field of disaster shelters and, in particular, to a high force shelter and life support system that protects its inhabitants from tornadoes, hurricanes, earthquakes and other force generating disasters.
History has shown that hurricanes, sudden tornadoes, and devastating earthquakes, can cause a significant loss of property and, more importantly, of human life. There are many ways to protect oneself from such catastrophic events. For example, cellars that are covered with concrete slabs or other sturdy rigid foundations may remain intact when in a worst case scenario the upper housing structure is destroyed or blown away. However, there is no guarantee that the structures above these cellars will not crash downward into the cellar. Further, modular or mobile homes are built upon slabs and, accordingly, offer no protection against the devastating forces of a hurricane, tornado or earthquake.
A tornado may have swirling winds forces that can reach speeds of over 200 MPH. This kind of wind force creates a type of suction force that has a tendency to pick up all sorts of structures to transport the same to a different location. Accordingly, it is important that people have strong shelters available within a short distance or in close proximity to where they live.
A number of underground shelters have been developed to protect inhabitants in the event of a hurricane or tornado. U.S. Pat. No. 5,829,208 issued Nov. 3, 1998 describes a steel reinforced cylindrical structure having a bell-shaped end at one end and a spigot at the other end. It is of a size to comfortably protect up to 10 people within its interior. One end of the structure is closed by a concrete end wall while the other end is partially closed by a slanting concrete deflector wall. The deflector wall at its upper end may or may not be fastened to the top of the cylindrical structure.
Although this structure could protect individuals from minor inclement weather, the design creates inherent problems during a disaster. First, concrete will leak while under ground for a long period of time. Thus, during a hurricane, the structure will leak, and the porous character inherent in concrete will only be augmented by winter freezing. Second, the cylindrical structure will not provide protection from a tornado, or strong hurricane winds. While cylinders provide protection from an evenly distributed force, a point force will crush the structure. Third, the structure is designed to be only partially underground which makes it vulnerable to heavy winds and complete exposure during a tornado, which would render the structure useless, and would crumble in the event of an earthquake. Fourth, this structure does not provide a life support system to provide fresh air in the event the disaster lasts longer than a few hours. Fifth, there are no communications devices in the event of a medical emergency, or inability to escape from the shelter because of heavy debris. Sixth, this shelter contains no structural elements that would prevent uplifting during times of high ground water. Finally, this shelter provides a single means of entry and egress, creating a possibility that inhabitants will be trapped by fallen debris.
U.S. Pat. No. 4,615,158 issued Oct. 7, 1986 describes a tornado shelter, specially adapted for use with mobile home lots. The shelter is an underground enclosure defined by an annular sidewall and a top and bottom. The top enclosure has an entrance and egress passageway in communication with both the enclosure and the bottom of a mobile home.
Although this shelter may provide protection from a low force tornado which lasts for a short period of time, or a short lived weak hurricane, this shelter is not suited to protect inhabitants from a Force 5 tornado, forceful hurricane or earth quake. The invention has a cylindrical shape, which only acts to disperse forces evenly over the entire structure when the force acts upon the structure evenly. If a hard force hits just one area of the structure, it will tend to buckle and destroy its integrity. The shelter is constructed from steel cylinder side walls and a concrete floor, which has a tendency to leak over time This shelter provides an entranceway made of a removable board from the floor of the mobile home, followed by a tube connecting the mobile home to the shelter. Therefore, if the mobile home is pulled off its foundation, the entrance tube will be openly exposed to the forceful winds of a tornado or hurricane. Since this tube is not in the ground, the result will most likely be a complete destruction of the entrance tube, and therefore full exposure of the inside of the shelter to the forceful winds and rain. Finally, this shelter also lacks all life sustaining mechanisms.
U.S. Pat. No. 4,955,166 issued Sep. 11, 1990 describes a generally spherical tornado shelter for safely housing and protecting people and things underground in the form of a truncated globe that is formed from a curved sidewall and terminates in the floor at the lower end thereof. The spherical shelter is preferably made of fiberglass and has a generally rectangular entrance formed in spaced relation to the central axis and provides a doorway into the interior of the structure. A plurality of steps lead from the entrance down the floor and enables people to conveniently walk through the entrance, down the steps, into and back up from the shelter.
Although this invention may provide protection from a low force tornado, this shelter has a structural design which will render the invention vulnerable in the event of a high force tornado or hurricane. Although made of fiberglass and virtually leak proof, the spherical shape is inherently weak when acted upon by point forces. The entrance is rectangular in shape and therefore susceptible to destruction by heavy force winds. Finally, even if the entrance remains intact through the disaster, a large amount of debris may become packed against the doorway, trapping the inhabitants inside.
Therefore, there is a need for a disaster shelter which provides protection from a tornado, hurricane, earthquake, chemical or biological disaster, that will not leak while under ground for a long period of time, that will not be crushed by a point force upon the structure, that provides a life support system to provide fresh air in the event the disaster lasts longer than a few hours that provides a communications device in the event of a medical emergency, or inability to escape from the shelter because of heavy debris, that will not be lifted from the ground in the event of high water table, that eliminates the possibility that inhabitants will be trapped by fallen debris.
The present invention is a disaster shelter for mounting under ground such that shelterists are protected from natural disasters such as tornadoes and hurricanes, and from human made disasters, such as bombs, armed invasions or the like. In its most basic form, the disaster shelter includes an entranceway having at least one air vent and a substantially hollow paraboloid shaped shelter cell. The shelter cell includes a paraboloid focus portion attached to the entranceway and paraboloid base portion disposed opposite the entranceway. A gravity ring is attached to the paraboloid base portion and is dimensioned such that the shelter is constrained within the ground when the water table reaches ground level.
The preferred disaster shelter includes a life support system made up of an air intake duct, an air filter, a blower and at least one battery . The air filter is preferably a highly efficient particulate air filter that filters particles from the air. The preferred blower includes an exhaust disposed within said shelter cell and wherein said exhaust is positioned to create cyclonic air movement within said shelter cell. The preferred battery comprises is a one twelve volt deep cycle battery having sufficient electrical energy, when fully charged, to power the blower to supply between 40 and 60 cubic feet per minute of air for six days. In some embodiments the battery is charged by a battery charger, such a solar panel.
The preferred entranceway includes a substantially cylindrical manway attached to the focus portion of the shelter cell. A hatch dome ring is disposed about, and extends outward from, the manway and a hatch dome cover is removably attached to the hatch dome ring such that the hatch dome cover forms a weather resistant seal with the hatch dome ring The preferred manway includes an air inlet and an air outlet, while the preferred hatch dome ring includes at least one inlet vent opening and at least one outlet vent opening. In such an embodiment, it is preferred that inlet vent opening and outlet vent opening be dimensioned and disposed relative to the air inlet and air outlet such that rain is prevented from entering the air inlet and air outlet. The preferred hatch dome cover is hatch dome ring form a substantially continuous surface having an angle of incidence of less than twenty degrees in order to protect the shelter from damage due to flying debris.
The preferred disaster shelter is manufactured of structural fiberglass that is capable of withstanding up to ten pounds per square inch of overpressure and an earthquake of an intensity of up to 8.5 on a Richter scale. An emergency escape manway is disposed through a side wall of the preferred shelter cell to allow egress in the event that the hatch dome cover cannot be opened. Finally, the preferred shelter includes a communications device, such as a two-way radio, for communicating with the outside world. In this preferred shelter, the two-way radio includes a retractable antenna to avoid damage during a tornado or other disaster.
Therefore, it is an aspect of the invention to provide a disaster shelter that provides protection from a tornado, hurricane, earthquake, chemical or biological disaster.
It is a further aspect of the invention to provide a disaster shelter that will not leak while under ground for a long period of time.
It is a further aspect of the invention to provide a disaster shelter that will not be crushed by a point force upon the structure.
It is a further aspect of the invention to provide a disaster shelter that includes a life support system for maintaining breathable air within the shelter.
It is a further aspect of the invention to provide a disaster shelter that remains restrained in the ground in areas of high water tables without the need for cables or other wires that can damage the shelter during an earthquake or other ground shock.
It is a further aspect of the invention to provide a disaster shelter that eliminates the possibility that inhabitants will be trapped by fallen debris.
It is a further aspect of the invention to provide a disaster shelter that includes a battery operated blower for circulating air within the shelter.
It is a further aspect of the invention to provide a disaster shelter that includes a battery operated communications device.
These aspects of the invention are not meant to be exclusive and other features, aspects, and advantages of the present invention will be readily apparent to those of ordinary skill in the art when read in conjunction with the following description, appended claims and accompanying drawings.